1. Field of the Invention
The present invention relates to equipment utilized in the manufacture of semiconductor integrated circuits (IC) and, in particular, to utilization of a yttrium oxide (Y2O3) coating on the anodized aluminum alloy components utilized in a semiconductor integrated circuit vacuum process chamber to improve corrosion resistance and erosion.
2. Discussion of the Related Art
Corrosion/erosion resistance is a critical property for parts used in IC fabrication vacuum chambers, where both corrosive chemistries and high-energy plasma bombardment reduce component lifetime and create contamination problems.
Anodized aluminum alloy is a primary material used in making components utilized in IC processing chambers. However, the high concentration of impurities contained in conventional aluminum alloy causes formation of precipitates in the alloy which, in turn, cause internal cracks in the anodization layer. The integrity of the anodization layer is, thus, deteriorated and its corrosion resistance is severely damaged. The impurity concentration (wt. %) of xe2x80x9cconventionalxe2x80x9d aluminum alloy, such as 6061, is as follows: Mg=0.8-1.20; Cu=0.15-0.40; Zn=max. 0.25; Mn=max. 0.15; Fe=max. 0.70; Si=0.40-0.80; Others=max. 0.15
More recently, high purity aluminum alloy material has been developed, resulting in minimal internal cracking in the anodization layer. Current data shows that chamber parts made from high purity aluminum alloy materials perform much better than those made from conventional alloy xe2x80x9cHigh purityxe2x80x9d aluminum alloy means aluminum alloy with all impurities other than Mg being less than about 0.1 wt. % each, particularly Si, Fe and Cu.
Although high purity anodized aluminum alloy has a much better corrosion/erosion rate than the traditional anodized aluminum alloy, the anodization layer will still be attacked by the aggressive chamber environment after prolonged usage. The resulting need to replace parts reduces tool up-time and increases the cost of ownership.
Therefore there is always a need to continuously improve the lifetime of the aluminum alloy chamber components.
We are aware that yttrium oxide coatings have been used on anodized aluminum in the automobile and aerospace industries.
We have found that applying a ceramic-based surface protective layer, a yttrium oxide (Y2O3) coating, on the anodized surface of aluminum alloy chamber components improves the resistance of the anodized surface to corrosion and erosion by a factor of 5xc3x97 over the anodized surface alone, particularly in the fluorine/oxygen plasma environment typically used in fabricating ICs.
A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description and accompanying drawings that set forth an embodiment in which the principles of the invention are utilized.